If you personally had a 'bad experience' report the member of staff, complain. As for third party observations of other passengers experience it is hard to know the full context, but if its clearly excessive complain.
We have raised complaints with Irish Rail to ensure the RPU staff show their ID badges clearly when conducting a check. Demand to see the ID card if not shown, they must have the ID and a warrant card.
Its not a pleasant job and I have to admit we have complained to Irish Rail concerning the very superficial nature of ticket checks, we are now seeing a more in-depth check so this will catch the professional evaders who fake tickets, ID and so on.